40 years later, genomics could let Vietnam identify war dead

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Forty years later, the families of those lost during the Cold War combat in Vietnam may finally get their wish: a definitive account of what happened to their loved ones and, at this point, their ancestors. The march of progress in genetic analysis could give them this chance, as the country prepares to host the largest mass identification effort in history, potentially involving hundreds of thousands of bodies in the end.

Genomics pioneer Craig Venter told Nature that when he was a 21-year-old serving in the medical corps at the time, he “never imagined that such a project could ever become possible… We thought of body counts as statistics — now, decades later, it may be possible to put names to them.”

Vietnam’s Viet-Laos cemetery contains the remains of thousands of people who died in the Vietnam War — but most are still unidentified.

The difficulty in identifying the bodies comes down to several unique aspects of Vietnam and the conflict there, not all of which have been solved just yet. The first is the condition of each individual body — a lot of time has passed, and these skeletons have been sitting in a very biologically active part of the world. Natural decay happens very quickly in Vietnam, and any DNA trapped in the bones will be in a much weaker state than DNA trapped for an equivalent amount time in, say, the northern Balkans. It’s only with cutting-edge techniques in DNA “amplification” (repeated duplication to create testable amounts of DNA from a tiny sample) and analysis that scientists can offer a way forward.

Beyond that, there is the grisly reality of how these bodies have been handled, collectively. Many have been buried, unidentified, in cemeteries, but many others are in mass graves both known and unknown. Many of those mass graves have already been exhumed — poorly — which also complicates matters. These graves, both large and small, were dug from the early 1950s through to well beyond the withdrawal of American forces in 1975; there are a lot of them, and they are in a wide and frustrating variety of conditions.

The genomics revolution really does come in boring little kits like this one.

Once you actually have your sample from a body, though, that’s when modern genomics can step in. A sample of bone is broken down to a powder and any surviving DNA is extracted, amplified, and sequenced. Quick and accurate annotation tech chews through this sample and notes enough markers that it’s virtually impossible to get a false match with another, similarly annotated sample. Markers is chosen specifically for being good differentiators between families, populations, and individuals.

Here, the real problem crops up, in the form of community involvement. Though there’s significant will to get this project done, it needs a very, very large number of modern Vietnamese to contribute cheek swabs, along with their family information. As mentioned, the marker-maps coming from these bodies are only remotely helpful when you have a known standard against which to check them. That means you need a good understanding of the distribution of those markers in the Vietnamese population overall, and within certain local populations.

It’s telling about the progress of genetic testing technology, that the means to achieve all this comes in little pre-packaged kits from biotech giant Qiagen. They won’t achieve quite the comprehensive sequencing and annotation we’d want for a more general genetic analysis, the sort of detail-oriented look being done at the 1,000 Genomes Project and elsewhere, but that’s why it can proceed so efficiently. It will require $25 million worth of upgrades to the country’s three genetic testing labs, but the proposed identification process should be able to identify as many as 10,000 people per year.

Depressingly, even at peak throughput, it will still take at least several years to finish.